Studies of Nu-mu to Nu-e Oscillation Appearance in the MINOS Experiment

Abstract

The MINOS experiment uses a long baseline neutrino beam, measured 1 km downstream from its origin in the Near Detector at Fermilab, and 734 km later in the large underground Far Detector in the Soudan mine. By comparing these two measurements, MINOS can probe the atmospheric domain of the neutrino oscillation phenomenology with unprecedented precision. Besides the ability to perform a world leading determination of the Δm$2\atop{23}$ and θ23 parameters, via vμ flux disappearance, MINOS has the potential to make a leading measurement of vμ → ve oscillations in the atmospheric sector by looking for ve appearance at the Far Detector. The observation of ve appearance, tantamount to establishing a non-zero value of the θ13 mixing angle, opens the way to studies of CP violation in the leptonic sector, the neutrino spectral mass pattern ordering and neutrino oscillations in matter, the driving motivations of the next generation of neutrino experiments. In this thesis, we study the MINOS potential for measuring θ13 in the context of the MINOS Mock Data Challenge using a multivariate discriminant analysis method. We show the method's validity in the application to ve event classification and background identification, as well as in its ability to identify a ve signal in a Mock Data sample generated with undisclosed parameters. An independent shower reconstruction method based on three-dimensional hit matching and clustering was developed, providing several useful discriminator variables used in the multivariate analysis method. We also demonstrate that within 2 years of running, MINOS has the potential to improve the current best limit on θ13, from the CHOOZ experiment, by a factor of 2.